1. Field of the Invention
The present invention relates to a method and device for forming a wiring harness comprising a plurality of conductors with their ends either engaged to a connector or remaining bare for later connection. The inventive method and device results in each connector or group of bare ends of the wiring harness having a predetermined geographic position corresponding to a desired coupling position to enable the connector or group of bare ends to be engaged to equipment to be interconnected by the wiring harness. Each conductor of the final wiring harness follows a predetermined path inside the harness between its ends, such paths having common portions along which the conductors are bound together. The invention applies more particularly, although not exclusively, to the formation of wiring harnesses for connecting together numerous pieces of electric, electronic or other equipment required in automobiles, aircraft or other systems.
Conventionally, such wiring harnesses are made by representing the paths of the different conductors forming the wiring harness graphically on a sheet of paper disposed on a table, under a transparent plate formed with a plurality of holes for receiving guiding pins for maintaining the conductors temporarily in position along their path.
For each conductor to be positioned, the assembler must first of all identify it, then, by means of technical documentation, search among the plurality of paths for the one which corresponds to the conductor he has just identified. The assembler may then position the conductor following the plot of its path, and holding it there by means of guide pins disposed, by the assembler, in appropriate positions along the path. The assembler must of course begin this set of operations again for each conductor of the harness.
Such work is obviously fastidious and errors are practically inevitable, considering both the length of the tables and the fact that the formation of such harnesses may use several hundred conductors. Even though a "skeleton" of the harness is represented on the table, the assembler finds himself in fact in front of a veritable "jumble" of interlaced conductors which are difficult to control.
The object of the present invention is to overcome these drawbacks, and provide a method and device for automatically forming such wiring harnesses.
2. Prior Art
French Patent application FR 90 13137 by Claude Ricard filed on Oct. 17, 1990 describes processes and devices that begin the automatic making of cable bundles or wiring harness by first gathering multiple ends of selected wire sections of the bundle and engage them either in an end clamp for transfer by a supply conveyor or in a connector which is then engaged in a component clamp for transfer by the same supply conveyor. This invention intends that both the end clamps and the component clamps be respectively disengaged from the multiple ends engaged by the end clamps and the connectors engaged by the component clamps when the harness is ready to interconnect the equipment intended to form a desired system.
French Patent FR 2,619,258 (Claude Ricard) filed Aug. 7, 1987, and U.S. Pat. No. 4,715,099 (YOSHIDA) of Dec. 29, 1987 described wiring machines wherein several conductor wires are transported by clamps which are placed on a supply conveyor associated with the machine, said clamps each holding one end of a wire section. The Ricard patent also describes the making of the supply conveyor and the clamps.
These machines are controlled by a programmable central computer. They automatically cut sections of wires whose length is determined by the program. Said machines strip the section ends and automatically perform crimping operations.
French Patent FR-A-2,555,397 describes another type of automatic machine and a connection device for simple bundles shown in FIGS. 7 to 11 of the patent.
The above patents, and, in particular, the French Patent Application 90 13137 (Claude Ricard) teach methods and devices for preparing cable bundles.
However, automatic wiring machines made according to these patents only produce bundles in which the interconnection of multiple ends have been completed. U.S. Pat. No. 5,083,369 to Cerda which proceeds in a different manner than the prior art devices discussed above, is directed to a method and a device wherein a wiring harness made up of a plurality of sections of wire is first produced and then the common ends of the harness further engaged to different connectors for later engagement to electrical equipment to be interconnected as a system.
Although, all the above prior art have made it possible to automate part of the production which was previously performed largely by hand, the bundles made with connectors engaged must be manually separated into branches by creating bypasses or nodes, and then the wires from different branches interconnected or as in the Cerda patent the bundles made without connectors must have branch ends manually engaged to the connectors.